While sending HE caps to FW the length parameter is not
updated, resulting in incorrect value for 2 GHz.
To fix this initialize the HE caps length before sending
WMI_VDEV_SET_IE_PARAM_CMDID.
Change-Id: I2126e02f82f48a0b3110bc7e1dbee887d2f8b0db
CRs-Fixed: 3250116